Research On The Generation-side Converter Of Wind Power System Based On Direct Torque Control

As the indispensable access to the short of traditional energy and the environment protection, wind power is used more and more in the world recently. This thesis is a part of the project of 1.5MW wind power generation energy conversion system which is applied to the variable speed constant frequency wind power system (VSCF). The focus is on the control method of generator-side converter in the power conversion system.The state of wind power is summarized, and all kinds of VSCF technologies are drawn to comparisions. The direct-drive wind power generation system includs permanent magnet synchronous generator (PMSG), generator-side converter and grid-side converter. The generation-side inverter and it's control technologies are analysed, and the mathematical models of PMSG in different coordinate system are established.In this thesis the basic principle of Direct Torque Control (DTC) is analyzed. Some key problems are solved including detecting the roter initial position, constructing the vector table under generator model and counting flux linkage reference. The DTC system of PMSG without the position sensor is proposed . Aiming at the problems of conventional DTC system, for example the resistance variety, the flux integral saturation and the switch frequency variety, ameliorative methods are proposed. Because there is no position sensor on the rotor, the position sensor-less technology is researched.In this thesis the control method of generator-side converter based on DTC theory used in the direct-drive wind power syetem is researched. In the simulation circumstance, the advanced flux observer and conventional flux linkage integral are compered with each other. The method of rotor position estimate based on generator antielectromotive is effective. At last, the experiment roof is built, and the control program is designed. The experimental results verified the analysis in this thesis.